Review of NIOSH Response Paper: July 10, 2015 

Robert Anigstein and John Mauro, SC&A 

November 3, 2015 
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Finding 2: Betatron Operator Beta Doses 

• Skin doses from uranium 

o New SC&A analysis used intermittent exposure model developed by NIOSH for irradiated steel 

o NIOSH calculations based on continuous irradiation of uranium 

o SC&A created more realistic MCNPX model of uranium disk to simulate photoactivation 

• Skin doses from irradiated steel 

o SC&A verified NIOSH model 

o SC&A estimates 0–1% lower due to different calculations of betatron beam intensity 

• NIOSH skin dose estimates bounding and claimant favorable 

o NIOSH may wish to adopt lower, more realistic skin doses from uranium 
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Finding 10: Betatron Operator Gamma Dose 

•	 NIOSH response: 

o	 Betatron operator photon exposure scenario only used for doses to the skin of the hands and 

forearms—confirmed by SC&A 

o	 Hands and forearms exposed to betatron only 1⁄2 time, remainder of time shielded by body 

•	 SC&A reply: 

o	 Photograph shows betatron operator holding his left hand and forearm above his shoulders and his 

right arm at the side of his body 

o	 NIOSH should assume hands and forearms exposed to betatron full time 

o	 Recommended skin dose to hands/forearms: 10.225 rad (air kerma) × 0.654 rem/rad = 6.687 rem/y 
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Betatron Radiography of the Axle of a Power Shovel Cast at GSI 
Finding 5: Adding Betatron Operator Dose to Radium Radiography Dose
 

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•	 NIOSH response: 

o	 Setup time: 15 minutes between shots—15 min/shot × 10 shots/shift = 150 min/shift = 2.5 h/shift 

o	 Radiographic exposures: 30% × 8 h = 2.4 h/shift 

o	 Maximum time left for work in betatron: 8 h - 2.5 h - 2.4 h = 3.1 h ÷ 8 h = 38.75% 

o	 Assumption that same radiographer performed all uranium radiography represents unjustified bias 

•	 SC&A Reply: 

o	 Radium Era worker said he spent 50%–60% of each radiography shift in betatron building 

o	 Worker’s film dosimetry records consistent with the agreed-upon estimates of external exposures 

o	 Upper end of range: 60% = plausible upper bound of time in betatron building 

o	 Time between shots: 

•	 Radiographer took 12–15 s to transport radium source from lead pig and position it for the exposure 

•	 Film was most likely stored nearby (in radiographer’s office inside facility in #6 Building) 

•	 Films developed in batches during long shots 

o	 Average shot: 2.4 h ÷ 10 = 0.24 h � 14 min 

o	 Range: 1–70 min (reported by GSI official to AEC inspector) 

• Casting larger than 1 film, required several shots—no need to replace casting after every shot 

o	 One worker could perform radium radiography and all betatron radiography of uranium, resulting in 

higher skin and neutron doses 

•	 Maximum time on uranium radiography = 437.5 h/y � 13.5% of all shifts 
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Finding 6: Layout Man Beta Dose 

• NIOSH response: 

o All castings irradiated intermittently (setup—expose—setup—expose, etc.) 

o Layout man spent most of shift on one casting (single casting scenario) 

o Often spent 15 min on freshly irradiated casting—total 10% of shift (interrupting casting scenario) 

o Same amount of time on each casting, whether long or short shot 

o 90% of time on short shots—10% on long shots 

• SC&A reply: accept NIOSH model as bounding and claimant favorable, except for time on long vs. short shots 

o Long shots took longer to mark up: steel much thicker, therefore had more defects 

• Account of GSI worker at last W-G meeting: 

o The bigger the casting . . . [the] more defects 

o Missile tubes for Polaris submarine had fewer defects 

• Polaris missile tubes <5-in thick (Cdr. John Harrop, USN [ret], former engineering officer on Polaris submarines) 

• Cavity . . . defect is partly a function of section thickness designed into casting (American Foundry Society) 

• The larger and more complex the casting, the [more likely the] . . . defects (William C. Thurber, metallurgist) 

o SC&A recommendation: 

• Maximum ratio of time per casting long:short = 5:1 based on time in betatron (75 min:15 min) 

• Minimum ratio 1:1 

• Average ratio 3:1—for n long shots and 9n short shots, fraction of time on long shots = % 
 

 

 

 

 

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Annual Doses to Skin of Layout Man from Beta Rays Emitted by Irradiated Steel 

Dose (rad/y) Skin on: SC&A-1a SC&A-2b NIOSH-1c NIOSH-2d Newe 

Hands and forearms 1.89 0.278 0.807 0.264 0.405 

Rest of body 1.14 0.178 0.463 0.147 0.224 

a SC&A review of Appendix BB, Rev. 1 (2014) 

b Same scenario as SC&A-1 but recalculated using intermittent exposure algorithm 

c Appendix BB, Rev. 1 (2014) 

d NIOSH (July 10, 2015) 

e Same scenario as NIOSH-2, recalculated by SC&A assuming 25% of time spent marking up long shots 

o Minor contribution vs. 9 R/y photon exposure 
ISSUE RESOLUTION MATRIX FOR SC&A FINDINGS ON APPENDIX BB, REV. 1
 

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• Issue 1 (neutron dose rates): NIOSH agreed to resolve this issue. 

• Issue 2 (beta dose to skin of betatron operator): SC&A agrees that NIOSH estimates are bounding. 

• Issue 3 (no dedicated radiographic facility in No. 6 Building prior to 1955): NIOSH agreed to resolve this 

issue. 

• Issue 4 (maximum of triangular distribution of photon exposures for 1961 should be 12 R/y): NIOSH 

agreed to resolve this issue. 

• Issue 5 (combined exposures to 226Ra and betatron operations during 1952–1962): In progress, pending 

resolution of differences between DCAS and SC&A. 

• Issue 6 (beta skin dose to layout man): In progress, pending resolution of differences between DCAS 

and SC&A. 

• Issue 7 (uranium inhalation from metal handling in 1966): NIOSH agreed to resolve this issue. 

• Issue 8 (ingestion intakes not consistent with OCAS-TIB-009): NIOSH agreed to resolve this issue. 

• Issue 9 (ingestion intakes during residual period): NIOSH agreed to resolve this issue. 

• Issue 10 (external exposure of betatron operator): In progress, pending resolution of differences between 

DCAS and SC&A. 
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POTENTIAL IMPACTS ON PAST AND FUTURE CLAIMS
 

• Issue 1 (neutron dose rates): neutron doses higher 

• Issue 2 (beta dose to skin of betatron operator): beta skin doses lower 

• Issue 3 (no dedicated radiographic facility in No. 6 Building prior to 1955): photon doses higher 1952–55 

• Issue 4 (maximum of triangular distribution of photon exposures for 1961 should be 12 R/y): photon 

doses lower in 1961 

• Issue 5 (combined exposures to 226Ra and betatron operations during 1952–1962): neutron and beta 

skin doses higher during 1952–1962 

• Issue 6 (beta skin dose to layout man): beta skin doses lower 

• Issue 7 (uranium inhalation from metal handling in 1966): intake doubled during first 6 months of 1966 

• Issue 8 (ingestion intakes not consistent with OCAS-TIB-009): ingestion rates lower during operational 

period 

• Issue 9 (ingestion intakes during residual period): ingestion rates lower during residual period 

• Issue 10 (external exposure of betatron operator): doses to skin of hands and forearms higher